Abstract

The sintered Nd-Fe-B magnets with various rare earth (RE) contents were prepared using strip casting technique, and the dependence of the microstructures and coercivity on rare earth content was investigated. It is found that an appropriate higher rare earth content in magnets is beneficial to the formation of uniform distribution of the RE-rich phases in grain boundaries, which leads to a rapid growth in the coercivity of magnets with increasing the rare earth content from the range of 29 wt.% to 32 wt.%. Moreover, continuous thin layers of RE-rich phase were confirmed by scanning electron microscopy in details. We further demonstrate that the coercivity of magnets becomes stronger with an appropriate higher RE content using micromagnetic simulation.